Fair argument, mthd. The elevated rail lines I linked pictures to in the beginning were using early 20th century technology, which has since improved. Elevated rail lines are less oppressive than before. We can all agree on that. The reason I linked those images at the beginning has to do with the time period in which people first began experimenting with monorails, and were inspired by those type of very disruptive infrastructure projects.
But here's a question: are modern elevated rail transit lines really as non-intrusive as monorails? I don't think any conventional-rail system could be made to be as non-intrusive as a monorail, even if the support structure is made to look similar. At least not for the same cost.
And raising the guideway is also a technique monorails can use:
Sao Paulo monorail:
Even though the aesthetic argument has been slightly weakened as elevated rail lines have made technological improvements, I think there is still a strong case for monorails. If you are going to build a transit line that is mostly elevated, has steep grades, high ridership demands, and can't have devastating impacts on the community around it, Monorails are the clear 1st choice.